Chapter 18 Surgical Haemostasis Flashcards
What are the three main principles used to augment haemostasis?
- Reduction in blood flow to affected area
- Topical haemostatic agents
- Antifibrinolytics
What are the three main principles used to augment haemostasis and list examples of each.
-
Reduction in blood flow to affected area
- Topical vasoconstrictors
- Hypotension/hypothermia/reduced perfusion
- Distant control of blood flow
-
Topical haemostatic agents
- Mechanical
- Active
- Haemostatic sealants
-
Antifibrinolytics
- Serine protease inhibitor
- Lysine analogues
What are the three main principles used to augment haemostasis, list broad examples of each, and specific examples
-
Reduction in blood flow to affected area
- Topical vasoconstrictors
- Epinephrine 0.01 - 1 mg/kg
- Hypotension/hypothermia/reduced perfusion
- Distant control of blood flow
- Clamps or tourniquets
- Topical vasoconstrictors
-
Topical haemostatic agents
- Mechanical
- Collagen
- Gelatin
- Cellulose
- Polysaccharide spheres
- Bone wax
- Ostene
- Active
- Thrombin
- Alginates
- Haemostatic sealants
- Fibrin
- Synthetic sealants
- Mechanical
-
Antifibrinolytics
- Serine protease inhibitor
- Aprotinin
- Lysine analogues
- TXA
- Epsilon-aminocaproic acid
- Serine protease inhibitor
List vessels that can be permanently ligated (11 in total)
How long can the following vessels be ligated for?
Descending thoracic aorta
Pringle manouvre
Hepatic artery
Splenic artery and vein
Renal artery and vein
Abdominal aorta
5 - 10 mins: Descending thoracic aorta
10 - 15 mins: Pringle manouvre
30 mins: Hepatic artery
15 - 20 mins: Splenic artery and vein
30 mins: Renal artery and vein
30 mins: Abdominal aorta
How long can descending thoracic aorta be occluded for?
5 - 10 mins
How long can the pringle manouver be performed for
10 - 15 mins
How long can the hepatic artery be occluded for?
30 mins
How long can the renal artery and vein be occluded for
30 mins
How long can abdominal aorta be occluded for
30 mins
How long can splenic artery and vein be occluded for?
15 - 20 mins
What is an esmarch tourniquet
Esmarch tourniquets are usually made of a broad elastic material and are applied tightly from distal to proximal, thus exsanguinating the limb. The Esmarch bandage is then secured tightly at the proximal aspect of the limb, preventing blood from flowing into the limb during surgery; thus, the limb is not only prevented from bleeding but also has had the blood removed
What is the recommended pressure of a tourniquet?
100 mmHg above patients systolic BP
What is the formula for pressure exerted by a tourniquet
P is pressure (Pa)
T is bandage tension (N)
R is the radius of curvature of the limb (m)
W is bandage width (m).
What is recommended time limit for tourniquet
1.5 - 2 hours
(at which point muscle ATP stores are depleted)
Name 2 contraindications to (limb) exsanguination
Infection or neoplasia
What are the three categories of haemostatic agent
- Mechanical
- Active
- Haemostatic sealant
List 5 possible complications of haemostatic agents
- Exothermic reaction
- Volumetric swelling
- Immunogenic reaction
- FB reaction
- Inhibition of normal tissue healing
List 2 contraindications to use of haemostatic agents
- Auto-transfusion (can pass through 40 um filter!) planned
- Intravascularly
How do mechanical haemostatic agents work?
- Mechanical barrier –> tamponade
- Scaffold for clot formation
In vitro, which mechanical haemostatic agent performed best?
Microfibrillar collagen > collagen sponge > gelatin > cellulose
What is source of gelatin?
Porcine
(“Gelofoam”)
What mechanical and active haemostatic agents are often combined
Thrombin + gelatin
(N.B. Thrombin cant be combined with cellulose because cellulose –> acidic environment which inactivated thrombin)
In terms of action, how does gelatin differ from cellolose
Gelatin doesnt cause platelet aggregation
